Crosslinkable polymeric compositions with amine-functionalized interpolymers, methods for making the same, and articles made therefrom

ABSTRACT

Crosslinkable polymeric compositions comprising an ethylene-based polymer, an organic peroxide, and an amine-functionalized interpolymer. Such crosslinkable polymeric compositions and their crosslinked forms can be employed as polymeric layers in wire and cable applications, such as insulation in power cables.

REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. ProvisionalApplication No. 61/992,338, filed on May 13, 2014.

FIELD

Various embodiments of the present invention relate to crosslinkablepolymeric compositions comprising amine-functionalized interpolymers,methods of making the same, and articles made therefrom.

INTRODUCTION

Medium, high, and extra-high voltage (“MV,” “HV,” and “EHV”) cablestypically contain a crosslinked polymeric material as an insulationlayer, such as a crosslinked polyethylene. Such crosslinked polymericmaterials can be prepared from a crosslinkable polymeric compositionhaving a peroxide initiator. The peroxides used as initiators forradical crosslinking in such materials can undergo non-productivedecomposition during storage, particularly in the presence of an acid,thus reducing the cure potential of peroxide-containing crosslinkablecompositions. Although advances have been achieved in the field ofcrosslinkable polymeric compositions, improvements are still desired.

SUMMARY

One embodiment is a crosslinkable polymeric composition, comprising:

-   -   (a) an ethylene-based polymer;    -   (b) an organic peroxide; and    -   (c) an amine-functionalized interpolymer having incorporated        therein at least one type of amine-containing monomer.

Another embodiment is a crosslinkable polymeric composition, comprising:

-   -   (a) an ethylene-based amine-functionalized interpolymer; and    -   (b) an organic peroxide.

DETAILED DESCRIPTION

Various embodiments of the present invention concern crosslinkablepolymeric compositions comprising an ethylene-based polymer, an organicperoxide, and an amine-functionalized interpolymer. In some embodiments,the ethylene-based polymer and the amine-functionalized interpolymer canbe present as a single component (i.e., an ethylene-basedamine-functionalized interpolymer). Additional embodiments concerncrosslinked polymeric compositions prepared from such crosslinkablepolymeric compositions. Further embodiments concern coated conductorsand processes for producing coated conductors using the crosslinkablepolymeric compositions.

Crosslinkable Polymeric Composition

As noted above, one component of the crosslinkable polymericcompositions described herein is an ethylene-based polymer. As usedherein, “ethylene-based” polymers are polymers prepared from ethylenemonomers as the primary (i.e., greater than 50 weight percent (“wt %”))monomer component, though other co-monomers may also be employed.“Polymer” means a macromolecular compound prepared by reacting (i.e.,polymerizing) monomers of the same or different type, and includeshomopolymers and interpolymers. “Interpolymer” means a polymer preparedby the polymerization of at least two different monomer types. Thisgeneric term includes copolymers (usually employed to refer to polymersprepared from two different monomer types), and polymers prepared frommore than two different monomer types (e.g., terpolymers (threedifferent monomer types) and quaterpolymers (four different monomertypes)).

In various embodiments, the ethylene-based polymer can be an ethylenehomopolymer. As used herein, “homopolymer” denotes a polymer consistingof repeating units derived from a single monomer type, but does notexclude residual amounts of other components used in preparing thehomopolymer, such as chain transfer agents.

In an embodiment, the ethylene-based polymer can be anethylene/alpha-olefin (“α-olefin”) interpolymer having an α-olefincontent of at least 1 wt %, at least 5 wt %, at least 10 wt %, at least15 wt %, at least 20 wt %, or at least 25 wt % based on the entireinterpolymer weight. These interpolymers can have an α-olefin content ofless than 50 wt %, less than 45 wt %, less than 40 wt %, or less than 35wt % based on the entire interpolymer weight. When an α-olefin isemployed, the α-olefin can be a C₃₋₂₀ (i.e., having 3 to 20 carbonatoms) linear, branched or cyclic α-olefin. Examples of C₃₋₂₀ α-olefinsinclude propene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene,1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-octadecene. Theα-olefins can also have a cyclic structure such as cyclohexane orcyclopentane, resulting in an α-olefin such as 3-cyclohexyl-1-propene(allyl cyclohexane) and vinyl cyclohexane. Illustrativeethylene/α-olefin interpolymers include ethylene/propylene,ethylene/1-butene, ethylene/1-hexene, ethylene/1-octene,ethylene/propylene/1-octene, ethylene/propylene/1-butene, andethylene/1-butene/1-octene.

In various embodiments, the ethylene-based polymer can be used alone orin combination with one or more other types of ethylene-based polymers(e.g., a blend of two or more ethylene-based polymers that differ fromone another by monomer composition and content, catalytic method ofpreparation, etc). If a blend of ethylene-based polymers is employed,the polymers can be blended by any in-reactor or post-reactor process.

In various embodiments, the ethylene-based polymer can be selected fromthe group consisting of low-density polyethylene (“LDPE”),linear-low-density polyethylene (“LLDPE”), very-low-density polyethylene(“VLDPE”), and combinations of two or more thereof.

In an embodiment, the ethylene-based polymer can be an LDPE. LDPEs aregenerally highly branched ethylene homopolymers, and can be prepared viahigh pressure processes (i.e., HP-LDPE). LDPEs suitable for use hereincan have a density ranging from 0.91 to 0.94 g/cm³.

In various embodiments, the ethylene-based polymer is a high-pressureLDPE having a density of at least 0.915 g/cm³, but less than 0.94 g/cm³,or less than 0.93 g/cm³. Polymer densities provided herein aredetermined according to ASTM International (“ASTM”) method D792. LDPEssuitable for use herein can have a melt index (I₂) of less than 20 g/10min., or ranging from 0.1 to 10 g/10 min., from 0.5 to 5 g/10 min., from1 to 3 g/10 min., or an 12 of 2 g/10 min. Melt indices provided hereinare determined according to ASTM method D1238. Unless otherwise noted,melt indices are determined at 190° C. and 2.16 Kg (i.e., I₂).Generally, LDPEs have a broad molecular weight distribution (“MWD”)resulting in a relatively high polydispersity index (“PDI;” ratio ofweight-average molecular weight to number-average molecular weight).

In an embodiment, the ethylene-based polymer can be an LLDPE. LLDPEs aregenerally ethylene-based polymers having a heterogeneous distribution ofcomonomer (e.g., α-olefin monomer), and are characterized by short-chainbranching. For example, LLDPEs can be copolymers of ethylene andα-olefin monomers, such as those described above. LLDPEs suitable foruse herein can have a density ranging from 0.916 to 0.925 g/cm³. LLDPEssuitable for use herein can have a melt index (I₂) ranging from 1 to 20g/10 min., or from 3 to 8 g/10 min.

In an embodiment, the ethylene-based polymer can be a VLDPE. VLDPEs mayalso be known in the art as ultra-low-density polyethylenes, or ULDPEs.VLDPEs are generally ethylene-based polymers having a heterogeneousdistribution of comonomer (e.g., α-olefin monomer), and arecharacterized by short-chain branching. For example, VLDPEs can becopolymers of ethylene and α-olefin monomers, such as one or more ofthose α-olefin monomers described above. VLDPEs suitable for use hereincan have a density ranging from 0.87 to 0.915 g/cm³. VLDPEs suitable foruse herein can have a melt index (I₂) ranging from 0.1 to 20 g/10 min.,or from 0.3 to 5 g/10 min.

In an embodiment, the ethylene-based polymer can comprise a combinationof any two or more of the above-described ethylene-based polymers.

Production processes used for preparing ethylene-based polymers arewide, varied, and known in the art. Any conventional or hereafterdiscovered production process for producing ethylene-based polymershaving the properties described above may be employed for preparing theethylene-based polymers described herein. In general, polymerization canbe accomplished at conditions known in the art for Ziegler-Natta orKaminsky-Sinn type polymerization reactions, that is, at temperaturesfrom 0 to 250° C., or 30 or 200° C., and pressures from atmospheric to10,000 atmospheres (1,013 megaPascal (“MPa”)). In most polymerizationreactions, the molar ratio of catalyst to polymerizable compoundsemployed is from 10⁻¹²:1 to 10⁻¹:1, or from 10⁻⁹:1 to 10⁻⁵:1.

An example of an ethylene-based polymer suitable for use herein is ahigh-pressure low-density polyethylene (“HP-LDPE”), which can have adensity of 0.92 g/cc and a melt index of 2. Such HP-LDPEs are produced,for example, by The Dow Chemical Company, Midland, Mich., USA, and canbe utilized in commercially available compounds for power cableinsulation.

As noted above, the crosslinkable polymeric compositions describedherein comprise an organic peroxide. As used herein, “organic peroxide”denotes a peroxide having the structure: R¹—O—O—R², or R¹—O—O—R—O—O—R²,where each of R¹ and R² is a hydrocarbyl moiety, and R is ahydrocarbylene moiety. As used herein, “hydrocarbyl” denotes a univalentgroup formed by removing a hydrogen atom from a hydrocarbon (e.g. ethyl,phenyl) optionally having one or more heteroatoms. As used herein,“hydrocarbylene” denotes a divalent group formed by removing twohydrogen atoms from a hydrocarbon optionally having one or moreheteroatoms. The organic peroxide can be any dialkyl, diaryl, dialkaryl,or diaralkyl peroxide, having the same or differing alkyl, aryl,alkaryl, or aralkyl moieties. In an embodiment, each of R¹ and R² isindependently a C₁ to C₂₀ or C₁ to C₁₂ alkyl, aryl, alkaryl, or aralkylmoiety. In an embodiment, R can be a C₁ to C₂₀ or C₁ to C₁₂ alkylene,arylene, alkarylene, or aralkylene moiety. In various embodiments, R,R¹, and R² can have the same or a different number of carbon atoms andstructure, or any two of R, R¹, and R² can have the same number ofcarbon atoms while the third has a different number of carbon atoms andstructure.

Organic peroxides suitable for use herein include mono-functionalperoxides and di-functional peroxides. As used herein, “mono-functionalperoxides” denote peroxides having a single pair of covalently bondedoxygen atoms (e.g., having a structure R—O—O—R). As used herein,“di-functional peroxides” denote peroxides having two pairs ofcovalently bonded oxygen atoms (e.g., having a structure R—O—O—R—O—O—R).In an embodiment, the organic peroxide is a mono-functional peroxide.

Exemplary organic peroxides include dicumyl peroxide (“DCP”); tert-butylperoxybenzoate; di-tert-amyl peroxide (“DTAP”);bis(alpha-t-butyl-peroxyisopropyl) benzene (“BIPB”); isopropylcumylt-butyl peroxide; t-butylcumylperoxide; di-t-butyl peroxide;2,5-bis(t-butylperoxy)-2,5-dimethylhexane;2,5-bis(t-butylperoxy)-2,5-dimethylhexyne-3;1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane; isopropylcumylcumylperoxide; butyl 4,4-di(tert-butylperoxy) valerate;di(isopropylcumyl) peroxide; and mixtures of two or more thereof. Invarious embodiments, only a single type of organic peroxide is employed.In an embodiment, the organic peroxide is dicumyl peroxide.

As noted above, the crosslinkable polymeric composition furthercomprises an amine-functionalized interpolymer. Suchamine-functionalized interpolymers comprise at least one type ofamine-containing monomer. In various embodiments, theamine-functionalized interpolymer can be an interpolymer of one or moreolefin-type monomers (e.g., α-olefin monomers) and at least one type ofamine-containing monomer. In still other embodiments, theamine-functionalized interpolymer and the ethylene-based polymer can bea single interpolymer (i.e., an ethylene-based amine-functionalizedinterpolymer) comprising at least one type of amine-containing monomer.

Amine-containing monomers suitable for use in preparing theamine-functionalized interpolymer can be any monomer containing an aminegroup and having at least one point of unsaturation. Examples of suchmonomers include, but are not limited to, alkenyl amines (e.g.,vinylamine, allylamine, etc.) and aminoacrylates. The amine group on theamine-containing monomer can be primary, secondary, tertiary, ormixtures thereof. In various embodiments, the amine group of theamine-containing monomer can be secondary or tertiary. When the aminegroup of the amine-containing monomer is secondary or tertiary, thesubstituents on the amine group can be hydrocarbyl groups (e.g., alkylgroups) having from 1 to 20 carbon atoms, from 1 to 10 carbon atoms, orfrom 1 to 6 carbon atoms, and can be branched, cyclic, orstraight-chained, and saturated or unsaturated. Examples of suitablesubstituents on secondary or tertiary amine groups include, but are notlimited to, methyl, ethyl, and t-butyl.

In various embodiments, the amine-containing monomer can be anaminoacrylate. Examples of suitable aminoacrylates include, but are notlimited to, 2-(diethylamino)ethyl methacrylate, 2-(dimethylamino)ethylmethacrylate, 2-(t-butylamino)ethyl methacrylate, and combinationsthereof. In various embodiments, the amine-containing monomer isselected from the group consisting of 2-(diethylamino)ethylmethacrylate, 2-(dimethylamino)ethyl methacrylate, 2-(t-butylamino)ethylmethacrylate, and mixtures of two or more thereof.

Alpha-olefin monomers suitable for use in preparing theamine-functionalized interpolymer can be any α-olefin known or hereafterdiscovered in the art for preparing α-olefin-based polymers. As itpertains to the amine-functionalized interpolymer, the term “α-olefin”shall include ethylene. Examples of such monomers include, but are notlimited to, ethylene, or any C₃₋₂₀ linear, branched or cyclic α-olefin.Examples of C₃₋₂₀ α-olefins include propene, 1-butene,4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene,1-tetradecene, 1-hexadecene, and 1-octadecene. The α-olefins can alsohave a cyclic structure such as cyclohexane or cyclopentane, resultingin an α-olefin such as 3-cyclohexyl-1-propene (allyl cyclohexane) andvinyl cyclohexane. In various embodiments, the α-olefin monomer employedin preparing the amine-functionalized interpolymer is ethylene.

In one or more embodiments, the amine-containing interpolymer is anethylene/aminoacrylate copolymer. In further embodiments, theethylene/aminoacrylate can comprise a copolymer of low-densitypolyethylene either copolymerized or grafted with an aminoacryaltemonomer, such as those described above (e.g., 2-(diethylamino)ethylmethacrylate, 2-(dimethylamino)ethyl methacrylate, 2-(t-butylamino)ethylmethacrylate, and mixtures of two or more thereof).

Preparation of the amine-functionalized interpolymer can be accomplishedby any known or hereafter discovered methods in the art, includingcopolymerization and grafting techniques. An example of a suitablepreparation technique is provided in the Examples section, below.

In various embodiments, it is contemplated that the above-describedethylene-based polymer and the amine-containing interpolymer can beprepared simultaneously. For example, in a reactor where theethylene-based polymer is being prepared, the amine-containing monomercan be fed into the reactor to either copolymerize with a portion of themonomers used in preparing the ethylene-based polymer or graft with aportion of formed ethylene-based polymer. Thus, in various embodiments,the above-described ethylene-based polymer and the amine-containinginterpolymer can be a single component (i.e., an ethylene-basedamine-containing interpolymer). In these embodiments, the crosslinkablepolymeric composition can be a two-component-based system comprising theethylene-based amine-functionalized interpolymer and an organicperoxide.

The amount of amine-containing monomer employed in preparing theamine-functionalized interpolymer is not particularly limited and can bevaried according to need. In various embodiments, however, the amount ofamine-containing monomer employed in preparing the amine-functionalizedinterpolymer can range from 0.1 to 20 wt %, from 0.5 to 10 wt %, from 1to 5 wt %, or from 1 to 2 wt %, based on the combined weight of allamine-containing monomers and olefin-type monomers employed in preparingthe amine-functionalized interpolymer. In embodiments where theethylene-based polymer is also the amine-functionalized interpolymer,the amount of amine-containing monomer employed can range from 25 ppm to2 wt %, or from 25 ppm to 100 ppm, based on the entire weight of theethylene-based amine-functionalized interpolymer.

In various embodiments, the crosslinkable polymeric composition cancomprise the ethylene-based polymer in an amount ranging from 50 to 99wt %, from 80 to 99 wt %, from 90 to 99 wt %, or from 95 to 99 wt %,based on the entire crosslinkable polymeric composition weight.Additionally, the crosslinkable polymeric composition can comprise theorganic peroxide in an amount ranging from 0.1 to 5 wt %, from 0.1 to 3wt %, from 0.4 to 2 wt %, from 0.4 to 1.7 wt %, from 0.5 to 1.4 wt %, orfrom 0.7 to less than 1.0 wt %, based on the entire crosslinkablepolymeric composition weight.

In various embodiments, the amine-functionalized interpolymer can bepresent in the crosslinkable polymeric composition in an amountsufficient to result in an amine-functionalization equivalent in therange of from 25 parts per million (“ppm”) up to approximately 100 ppmbased on the entire weight of the crosslinkable polymeric composition.As an example for clarity, an amine-functionalized interpolymer with 2wt % aminoacrylate functionalization, which is utilized in a polymericcomposition at 0.5 wt % would yield (2 wt %×0.5 wt %) 100 ppm ofequivalent amine-functionalization.

Additionally, the amine-functionalized interpolymer can be present inthe crosslinkable polymeric composition in an amount ranging from 0.1 to5 wt %, from 0.2 to 2 wt %, or from 0.4 to 0.6 wt %, based on the entireweight of the crosslinkable polymeric composition. Of course, thedesired concentration of the amine-functionalized interpolymer will varydepending on the degree of amine-functionalization in the interpolymer.Amine-functionalized interpolymers having low amine content (e.g., 0.1wt % of the interpolymer) may be used in higher concentrations toachieve the desired amine-functionalization equivalent in the overallcrosslinkable polymer composition. On the other hand,amine-functionalized interpolymers having high amine content may be usedin lower concentrations.

In other embodiments, when the amine-functionalized interpolymer and theethylene-based polymer are prepared together, the resultingethylene-based amine-functionalized interpolymer can be present in anamount ranging from 1 to 99 wt %, from 50 to 99 wt %, from 80 to 99 wt%, from 90 to 99 wt %, or from 95 to 99 wt %, based on the entirecrosslinkable polymeric composition weight.

In still other embodiments, based on a molar amine content per gram ofcrosslinkable polymeric composition, the amine-functionalizedinterpolymer (whether present as an individual component or as anethylene-based amine-functionalized interpolymer) can be present in anamount sufficient to yield a molar amine content of 0.1 to 200micromoles of amine per gram of crosslinkable polymeric composition,from 0.1 to 100 micromoles of amine per gram of crosslinkable polymericcomposition, from 0.1 to 6 micromoles of amine per gram of crosslinkablepolymeric composition, from 0.2 to 2.5 micromoles of amine per gram ofcrosslinkable polymeric composition, or from 0.5 to 0.7 micromoles ofamine per gram of crosslinkable polymeric composition.

In addition to the components described above, the crosslinkablepolymeric composition may also contain one or more additives including,but not limited to, antioxidants, crosslinking coagents, processingaids, fillers, coupling agents, ultraviolet absorbers or stabilizers,antistatic agents, nucleating agents, slip agents, plasticizers,lubricants, viscosity control agents, tackifiers, anti-blocking agents,surfactants, extender oils, acid scavengers, flame retardants, and metaldeactivators. Additives, other than fillers, are typically used inamounts ranging from 0.01 or less to 10 or more wt % based on totalcomposition weight. Fillers are generally added in larger amountsalthough the amount can range from as low as 0.01 or less to 65 or morewt % based on the total composition weight. Illustrative examples offillers include clays, precipitated silica and silicates, fumed silica,calcium carbonate, ground minerals, aluminum trihydroxide, magnesiumhydroxide, and carbon blacks with typical arithmetic mean particle sizeslarger than 15 nanometers.

In various embodiments, the crosslinkable polymeric composition cancomprise one or more antioxidants. Exemplary antioxidants includehindered phenols (e.g., tetrakis [methylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)] methane), less-hinderedphenols, and semi-hindered phenols; phosphates, phosphites, andphosphonites (e.g., tris (2,4-di-t-butylphenyl) phosphate); thiocompounds (e.g., distearyl thiodipropionate, dilauryl thiodipropionate);various siloxanes; and various amines (e.g., polymerized2,2,4-trimethyl-1,2-dihydroquinoline). In various embodiments, theantioxidant is selected from the group consisting of distearylthiodipropionate, dilauryl thiodipropionate,octadecyl-3,5-di-t-butyl-4-hydroxyhydrocinnamate, benzenepropanoic acid,3,5-bis(1,1-dimethylethyl)-4-hydroxy-thiodi-2,1-ethanediyl ester,stearyl 3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate,octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate,2,4-bis(dodecylthiomethyl)-6-methylphenol,4,4′-thiobis(6-tert-butyl-m-cresol), 4,6-bis(octylthiomethyl)-o-cresol,1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, pentaerythritoltetrakis(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate),2′,3-bis[[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyl]]propionohydrazide, and mixtures of two or more thereof.Antioxidants, when present, can be used in amounts ranging from 0.01 to5 wt %, from 0.01 to 1 wt %, from 0.1 to 5 wt %, from 0.1 to 1 wt %, orfrom 0.1 to 0.5 wt %, based on the total weight of the crosslinkablepolymeric composition.

In various embodiments, the crosslinkable polymeric composition caninclude one or more crosslinking coagents. Examples of such crosslinkingcoagents include polyallyl crosslinking coagents, such as triallylisocyanurate (“TAIC”), triallyl cyanurate (“TAC”), triallyl trimellitate(“TA™”), triallyl orthoformate, pentaerythritol triallyl ether, triallylcitrate, and triallyl aconitate; ethoxylated bisphenol A dimethacrylate;α-methyl styrene dimer (“AMSD”); acrylate-based coagents, such astrimethylolpropane triacrylate (“TMPTA”), trimethylolpropanetrimethylacrylate (“TMPTMA”), 1,6-hexanediol diacrylate, pentaerythritoltetraacrylate, dipentaerythritol pentaacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, and propoxylated glyceryl triacrylate;vinyl-based coagents, such as polybutadiene having a high 1,2-vinylcontent, and trivinyl cyclohexane (“TVCH”); and other coagents asdescribed in U.S. Pat. Nos. 5,346,961 and 4,018,852. When employed, thecrosslinkable polymeric composition can comprise the crosslinkingcoagent(s) in an amount ranging from 0 to 3 wt %, from 0.1 to 3 wt %,from 0.5 to 3 wt %, from 0.7 to 3 wt %, from 1.0 to 3 wt %, or from 1.5to 3 wt %, based on the entire crosslinkable polymeric compositionweight.

In various embodiments, the crosslinkable polymeric composition cancomprise at least one component that is acidic or that has one or moreacidic decomposition products. As mentioned above and discussed in moredetail below, it is believed that acidic species in the crosslinkablepolymeric composition contribute to degradation of the organic peroxide,and thus loss of cure potential, via acid-catalyzed decomposition.Peroxide degradation in this manner does not result in the radicals thatinitiate polymer crosslinking and thus result in loss of cure potential.The source of the acidic component can vary greatly and is notparticularly limited. However, in various embodiments, the source of theacidic component can be any one or more of the additives describedabove, such as antioxidants, crosslinking coagents, and processing aids,among others. For example, acidic species can be generated by theoxidation of common stabilizers to yield, for example, sulfur-based,phosphorous-based, or carboxylic acids. In various embodiments, thesource of the acidic component can be an antioxidant. In still furtherembodiments, the source of the acidic component is distearyldithiopropionate.

Preparation of Crosslinkable Polymeric Composition

Preparation of the cross-linkable polymeric composition can comprisecompounding the above-described components. For example, compounding canbe performed by either (1) compounding all components into theethylene-based polymer, or (2) compounding all the components except forthe organic peroxide, which can be soaked in as described below.Compounding of the cross-linkable polymeric composition can be effectedby standard equipment known to those skilled in the art. Examples ofcompounding equipment are internal batch mixers, such as a Brabender™,Banbury™, or Bolling™ mixer. Alternatively, continuous single or twinscrew, mixers can be used, such as a Farrel™ continuous mixer, a Wernerand Pfleiderer™ twin screw mixer, or a Buss™ kneading continuousextruder. Compounding can be performed at a temperature of greater thanthe melting temperature of the ethylene-based polymer up to atemperature above which the ethylene-based polymer begins to degrade. Invarious embodiments, compounding can be performed at a temperatureranging from 100 to 200° C., or from 110 to 150° C.

Alternatively, in one or more embodiments, the ethylene-based polymerand any optional components can first be melt compounded according tothe above-described procedure and pelletized. The amine-functionalizedinterpolymer can then be added to the pellets, mixed at elevatedtemperature (e.g., 130° C.), then pressed, cooled, and cut into stripsto be extruded at elevated temperature (e.g., 200° C.) and pelletizedagain. Next, the organic peroxide and the cross-linking coagent, ifemployed, can be soaked into the resulting ethylene-based polymercompound, either simultaneously or sequentially. In an embodiment, theorganic peroxide and optional coagent can be premixed at the temperatureabove the melting temperature of the organic peroxide and optionalcoagent, whichever is greater, followed by soaking the ethylene-basedpolymer compound in the resulting mixture of the organic peroxide andoptional cross-linking coagent at a temperature ranging from 30 to 100°C., from 50 to 90° C., or from 60 to 80° C., for a period of timeranging from 1 to 168 hours, from 1 to 24 hours, or from 3 to 12 hours.

The resulting crosslinkable polymeric composition can have increasedresistance to loss of cure potential. Though not wishing to be bound bytheory, it is believed that the amine functionality imparted to thecrosslinkable polymeric composition by the amine-functionalizedinterpolymer improves retention of the cure potential of thecrosslinkable polymeric composition. Essentially, it is believed thatthe amine functionality inhibits or interferes with the acid-catalyzeddecomposition of the peroxide in the crosslinkable polymericcomposition, thus preserving cure potential.

In one or more embodiments, the crosslinkable polymeric composition hasan initial cure potential (CP₀) when crosslinked immediately uponpreparation of the crosslinkable polymeric composition, as described inthe following Examples, and measured as maximum torque (in-lbs) bymoving die rheometer at 182° C. Additionally, the crosslinkablepolymeric composition has a heat-aged cure potential CP₁₄ whencrosslinked after aging the crosslinkable polymeric composition at 70°C. and ambient pressure for 14 days, as described in the followingExamples, and measured as maximum torque (in-lbs) by moving dierheometer at 182° C. In various embodiments, the crosslinkable polymericcomposition has a ratio of CP₁₄ to CP₀ of at least 0.1, at least 0.2, atleast 0.3, at least 0.4, at least 0.5, at least 0.6, at least 0.7, atleast 0.8, or at least 0.9, and up to 1.1, or 1.

In one or more embodiments, the crosslinkable polymeric composition hasheat-aged cure potential CP₂₁ when crosslinked after aging thecrosslinkable polymeric composition at 70° C. and ambient pressure for21 days, as described in the following Examples, and measured as maximumtorque (in-lbs) by moving die rheometer at 182° C. In variousembodiments, the crosslinkable polymeric composition has a ratio of CP₂₁to CP₀ of at least 0.1, at least 0.2, at least 0.3, at least 0.4, atleast 0.5, at least 0.6, at least 0.7, at least 0.8, or at least 0.9,and up to 1.1, or 1.

Crosslinked Polymeric Composition

The above-described crosslinkable polymeric composition can be cured orallowed to cure in order to form a crosslinked ethylene-based polymer.Such curing can be performed by subjecting the crosslinkable polymericcomposition to elevated temperatures in a heated cure zone, which can bemaintained at a temperature in the range of 175 to 260° C. The heatedcure zone can be heated by pressurized steam or inductively heated bypressurized nitrogen gas. Thereafter, the crosslinked polymericcomposition can be cooled (e.g., to ambient temperature).

The crosslinking process can create volatile decomposition byproducts inthe crosslinked polymeric composition. The term “volatile decompositionproducts” denotes byproducts formed during the curing step, and possiblyduring the cooling step, by initiation of the organic peroxide. Suchbyproducts can comprise alkanes, such as methane. Followingcrosslinking, the crosslinked polymeric composition can undergodegassing to remove at least a portion of the volatile decompositionbyproducts. Degassing can be performed at a degassing temperature, adegassing pressure, and for a degassing time period to produce adegassed polymeric composition. In various embodiments, the degassingtemperature can range from 50 to 150° C., or from 60 to 80° C. In anembodiment, the degassing temperature is 65 to 75° C. Degassing can beconducted under standard atmosphere pressure (i.e., 101,325 Pa).

Coated Conductor

A cable comprising a conductor and an insulation layer can be preparedemploying the above-described crosslinkable polymeric composition.“Cable” and “power cable” mean at least one wire or optical fiber withina sheath, e.g., an insulation covering and/or a protective outer jacket.Typically, a cable is two or more wires or optical fibers boundtogether, usually in a common insulation covering and/or protectivejacket. The individual wires or fibers inside the sheath may be bare,covered or insulated. Combination cables may contain both electricalwires and optical fibers. Typical cable designs are illustrated in U.S.Pat. Nos. 5,246,783, 6,496,629 and 6,714,707. “Conductor” denotes one ormore wire(s) or fiber(s) for conducting heat, light, and/or electricity.The conductor may be a single-wire/fiber or a multi-wire/fiber and maybe in strand form or in tubular form. Non-limiting examples of suitableconductors include metals such as silver, gold, copper, carbon, andaluminum. The conductor may also be optical fiber made from either glassor plastic.

Such a cable can be prepared with various types of extruders (e.g.,single or twin screw types) by extruding the crosslinkable polymericcomposition onto the conductor, either directly or onto an intercedinglayer. A description of a conventional extruder can be found in U.S.Pat. No. 4,857,600. An example of co-extrusion and an extruder thereforecan be found in U.S. Pat. No. 5,575,965.

Following extrusion, the extruded cable can pass into a heated cure zonedownstream of the extrusion die to aid in crosslinking the crosslinkablepolymeric composition and thereby produce a crosslinked polymericcomposition. The heated cure zone can be maintained at a temperature inthe range of 175 to 260° C. In an embodiment, the heated cure zone is acontinuous vulcanization (“CV”) tube. In various embodiments, thecrosslinked polymeric composition can then be cooled and degassed, asdiscussed above.

Alternating current cables can be prepared according to the presentdisclosure, which can be low voltage, medium voltage, high voltage, orextra-high voltage cables. Further, direct current cables can beprepared according to the present disclosure, which can include high orextra-high voltage cables.

Test Methods

Moving Die Rheometer

Perform moving die rheometer (“MDR”) testing at 182° C. respectivelyaccording to the methods described in ASTM D5289 on an AlphaTechnologies MDR 2000. The cure potential is determined using an MDR,which applies an oscillatory strain on a molten sample held at 182° C.,while recording the torque. As the compound crosslinks, the torqueincreases to reach a steady torque maximum, Mh. The comparison of Mh asa function of thermal aging time (at 70° C., for example) provides ameans to compare the composition's ability to retain cure potential overlong storage times under near-ambient conditions.

Heat Aging

Samples are heat aged in jars sealed with MYLAR™ film under screw-on capwithin a laboratory oven at 70° C. Just enough material is removed fromthe jar after specified aging time for MDR testing, after which the jaris re-sealed and returned to the oven for further heat aging.

Preparation of Crosslinked Plaque Sample for Dissipation Factor Test

A sufficient amount of pelleted compound is compression molded to fillan 8″×8″×0.010″ frame. Compression molding is conducted using thefollowing sequence of conditions: i) 3 minutes at 125° C. and 125 psi,ii) 5 minutes at 125° C. and 2500 psi, iii) quench-cool, iv) removeexcess flashing, cut into pieces, and continue with additionalpress-protocol, v) 3 minutes at 125° C. and 500 psi, vi) 3 minutes at125° C. and 2500 psi, vii) increase temperature to 182° C. and hold 12minutes at 2500 psi, viii) quench cool.

Dissipation Factor

The 60-Hz dissipation factor is measured on 3-inch discs cut fromcrosslinked plaques of samples at a temperature of 120° C. and anelectrical stress of 25 kV/mm. This is performed by inserting the samplebetween the flat circular electrodes of a Soken sample holder/test cellModel DAC-OBE-7. The test cell is filled with oil, using Galden D03Perfluoro Polyether from Solvay Specialty Polymers, which is heated andcirculated using a temperature-controlled oil bath. Measurements aretaken 1 hour after the sample is inserted to ensure that the system isin thermal equilibrium at the target test temperature. A power supply isused to provide up to 60 Hz 10 kV test voltage. A Soken AutomaticSchering Bridge Model DAC-PSC-UA is utilized to measure the dissipationfactor with a Soken Model DAC-Cs-102A 1000 pF reference capacitor.

Density

Determine density according to ASTM D792.

Melt Index

Measure melt index, or I₂, in accordance with ASTM D1238, condition 190°C./2.16 kg, and report in grams eluted per 10 minutes.

Materials

The following materials are employed in the Examples, below.

The low-density polyethylene (“LDPE”) employed has a melt index (I₂) of2 g/10 min., a density of 0.920 g/cm³, and is produced by The DowChemical Company, Midland, Mich., USA.

2-(dimethylamino)ethyl methacrylate is commercially available from SigmaAldrich, St. Louis, Mo., USA.

2-(diethylamino)ethyl methacrylate is commercially available from SigmaAldrich, St. Louis, Mo., USA.

2-(t-butylamino)ethyl methacrylate is commercially available from SigmaAldrich, St. Louis, Mo., USA.

Propionaldehyde (97%) is commercially available from Sigma Aldrich, St.Louis, Mo., USA.

Tert-butyl peroxyacetate (50% by weight solution in isododecane) iscommercially available from Fisher Scientific, Pittsburgh Pa., USA.

n-Heptane is commercially available from Sigma Aldrich, St. Louis, Mo.,USA.

Ethylene monomer is commercially available from Praxair.

Distearyl thiodipropionate (“DSTDP;” antioxidant) is commerciallyavailable from Reagens, S.p.A, Bologna, Italy.

Cyanox™ 1790(tris[(4-tert-butyl-3-hydroxy-2,6-dimethylphenyl)methyl]-1,3,5-triazinane-2,4,6-trione;antioxidant) is commercially available from Cytec Industries, WoodlandPark, N.J., USA.

Dicumyl peroxide is commercially available from Arkema Inc.

EXAMPLES Example 1

Prepare a control ethylene polymer and three ethylene/aminoacrylatecopolymers according to the following method.

Undiluted aminoacrylate monomer (either 2-(dimethylamino)ethylmethacrylate, 2-(diethylamino)ethyl methacrylate, or2-(t-butylamino)ethyl methacrylate) is loaded into a 0.25-L glass supplyvessel, which is open to the atmosphere. As the chain transfer agent, afresh 250-mL bottle of undiluted propionaldehyde (97%) is used as thesupply vessel, which is open to the atmosphere. As the initiator,tert-butyl peroxyacetate (2.3 grams of a 50% by weight solution inisododecane) is combined with 500 mL of n-heptane and loaded into athird glass supply vessel. This solution is purged with nitrogen tominimize dissolved oxygen.

For the control sample, inject ethylene at 1,000 gm/hr (35.65 moles/hr),at a pressure of 2,000 bar, into an agitated (2,000 rpm) 54-mLhigh-pressure continuous stirred tank reactor (“CSTR”), with an externalheating jacket set at 187° C. Next, degas the propionaldehyde by an HPLCdegasser and then add to the ethylene stream at a pressure of 250 barand a rate of 3.46 gm/hr (60 millimoles/hr). Then the mixture iscompressed to 2,000 bar. The peroxide initiator is added to theethylene-propionaldehyde mixture at a pressure of 2,000 bar and a rateof 3.2×10⁻³ gm/hr (0.024 millimoles/hr) before the mixture enters thereactor.

The ethylene conversion to polymer is 10.5 wt % based on the mass ofethylene entering the reactor, and the average reaction temperature is220° C. An ethylene-based polymer having a melt index (I₂) of 4.5 g/10min. is obtained. Approximately 70 grams of ethylene-based polymer iscollected.

For the ethylene/aminoacrylate samples, undiluted aminoacrylate monomeris pumped at a pressure of 250 bar and a rate of 1.84 gm/hr (11.7millimoles/hr) through an HPLC degasser, and then into thepropionaldehyde stream, and mixed before the mixture is added to theethylene stream and compressed to 2,000 bar. The peroxide initiator isadded to the ethylene-propionaldehyde-aminoacrylate mixture at apressure of 2,000 bar and a rate of 4.6×10⁻³ gm/hr (0.036millimoles/hr), before the mixture enters the reactor.

The ethylene conversion to polymer is 11 wt % based on the mass ofethylene entering the reactor, and the average reaction temperature is218° C. An ethylene-based polymer having a melt index (I₂) of 5 g/10 minis obtained. Approximately 350 grams of ethylene/aminoacrylate polymeris collected.

The comparison above illustrates the method of sample preparation of anethylene-based amine-functionalized interpolymer useful in the presentinvention; the addition of the aminoacrylate has little impact on theethylene conversion or melt index of the resulting polymer.

The following ethylene/aminoacrylate copolymers are obtained accordingto the above-described procedure:

TABLE 1 Ethylene/Aminoacrylate Copolymer Properties Aminoacrylate Samplecontent Designation Aminoacrylate Type (wt %) A 2-(diethylamino)ethylmethacrylate 1.98 wt % B 2-(dimethylamino)ethyl methacrylate 1.66 wt % C2-(t-butylamino)ethyl methacrylate 1.30 wt %

Example 2

Prepare one comparative sample (“CS1”) and three samples (“S1-S3”)according to the formulations listed in Table 2, below.

TABLE 2 Compositions of CS1 and S1-S3 Component (wt %) CS1 S1 S2 S3 LDPE99.63 99.13 99.13 99.13 DSTDP 0.23 0.23 0.23 0.23 Cyanox ™ 1790 0.140.14 0.14 0.14 Ethylene/aminoacrylate “A” — 0.5 — —Ethylene/aminoacrylate “B” — — 0.5 — Ethylene/aminoacrylate “C” — — —0.5 Preblend Total: 100 100 100 100 Peroxide Soak: Preblend (wt %) 98.298.2 98.2 98.2 Dicumyl Peroxide (wt %) 1.8 1.8 1.8 1.8 AminoacrylateContent: Aminoacrylate content in 0 100 100 85 composition (ppm)Approximate micromoles of 0 0.58 0.58 0.59 amine groups per gram ofcomposition

The sample formulations shown in Table 2 are prepared according to thefollowing procedure. The LDPE, DSTDP and Cyanox 1790 are melt compoundedtogether in a Werner Pfleiderer twin-screw extruder (Model ZSK-30) andthen pelletized. A Brabender mixing bowl is then used at 130° C. and 30rpm to flux the stabilized LDPE. For the samples S1-S3, theethylene/aminoacrylate copolymer is added to the mixer, and the mixingprocess is continued for an additional 5 minutes. The resultingcompositions are pressed, cooled, and cut into strips to feed into asingle-screw extruder. Extrusion is performed at 200° C. melttemperature to form strands that can be pelletized into approximately ⅛″diameter pellets.

Next, the dicumyl peroxide is soaked into the samples as follows. First,100 g of pellets of the preblend are pre-heated in an oven for 4 hoursat 70° C. in 8-oz. glass jars. Molten dicumyl peroxide (˜55° C.) isadded to the jars. The jars are sealed with a MYLAR™ film under thescrew-on lid, and tumbled, returned to the oven for approximately 15minutes, then tumbled or shaken again to ensure that the pellet surfaceis dry (indicating the peroxide has been absorbed). The pellets are thenallowed to soak overnight in the oven at 70° C.

Samples are removed from the jar to evaluate the cure potential as afunction of thermal aging time. The samples are heat aged and their curepotential is determined using a Moving Die Rheometer (MDR) according tothe procedures described above. Results of these analyses are providedin Table 3, below.

TABLE 3 Heat-Aged Cure Potential Retention of CS1 and S1-S3 (valueslisted represent Mh in in-lbs) Days at 70° C. CS1 S1 S2 S3 0 3.19 3.173.19 2.66 4 3.25 3.36 3.25 2.66 7 2.66 3.36 3.39 2.72 13 0.16 3.39 3.282.73 21 (0.16)* 3.48 3.36 2.75 28 (0.16)* 3.47 2.53 2.69 CP₁₃/CP₀**0.05 >1 >1 >1 CP₂₁/CP₀  0.05 >1 >1 >1 *(inferred value based uponearlier cure measurements, for use in calculation of cure ratioCP_(x)/CP₀) **Note that CP₁₃/CP₀ is used as a reasonable approximationto CP₁₄/CP₀

As seen in Table 3, CS1 is found to lose its cure potential between 7and 13 days of thermal aging at 70° C., which is characteristic of theacid-catalyzed decomposition of the peroxide. However, for S1-S3, theaddition of a small amount of amine functionality through theethylene/aminoacrylate copolymer results in cure potential retention forover 4 weeks. This is a clear indication that the amine functionalitywithin the copolymer is mitigating the acid-catalyzed decomposition ofthe peroxide.

Example 3

Prepare each of CS1 and S1-S3 for determining dissipation factoraccording to the following procedure. Each of the samples prepared asdescribed in Example 2 is pressed into a 12-mil plaque and crosslinkedas described above. The resulting plaques are stored in a vacuum oven at60° C. for 4 days to remove volatile byproducts from the crosslinkingreaction. 3-inch disks are cut from the plaques and analyzed fordissipation factor according to the above-described Test Methods.Results are provided in Table 4, below.

TABLE 4 Dissipation Factor of CS1 and S1-S3 CS1 S1 S2 S3 DF at 120° C.and 25 kV/mm <0.1% <0.1% <0.1% <0.1%

In all cases, the samples have a dissipation factor of less than 0.1percent. This indicates that each one is suitable for use as insulationin high-voltage AC power cables.

Example 4

Prepare three additional Samples (S4-S6) by using a portion of thepreblend of CS1 (containing no peroxide) to dilute the preblends of S1and S2. Perform this dilution on a 2-roll mill (0.4-mm gap, 20 rpm,approximate mix time of 6 minutes, roll temperature of 115° C., duringwhich material is cut from the edges and fed into the center of the rollapproximately 10 times) to achieve the formulations in Table 5.

TABLE 5 Compositions of S4-S6 Component (wt %) S4 S5 S6 Preblend of CS150 75 50 Preblend of S1 50 25 — Preblend of S2 — — 50 Preblend Total:100 100 100 Peroxide Soak: Preblend (wt %) 98.2 98.2 98.2 DicumylPeroxide (wt %) 1.8 1.8 1.8 Aminoacrylate Content: Aminoacrylate contentin 50 25 50 composition (ppm) Approximate micromoles 0.29 0.15 0.29 ofamine groups per gram of compound

Milled sheets are then diced into small squares about 0.5 cm in size,and 50 g of the diluted and diced material is inserted into a 16-oz.jar. The dicumyl peroxide is soaked into the samples in a similarfashion as described in Example 2. First, the 50 g of each dicedmaterial is pre-heated in an oven for 4 hours at 70° C. in 16-oz. glassjars. Molten dicumyl peroxide (˜55° C.) is added to the jars. The jarsare sealed with a Mylar™ film under the screw-on lid, and tumbled,returned to the oven for approximately 15 minutes, then tumbled orshaken again to ensure that material surface is dry (indicating theperoxide has been absorbed). The material is then allowed to soakovernight in the oven at 70° C.

Samples are removed from the jar to evaluate the cure potential as afunction of thermal aging time. The samples are heat aged and their curepotential is determined using a Moving Die Rheometer (MDR) according tothe procedures described above. Results of these analyses are providedin Table 6, below.

TABLE 6 Heat-Aged Cure Potential Retention of S4-S6 (values listedrepresent Mh in in-lbs) Days of Aging at 70° C. S4 S5 S6 0 (2.66)* 2.502.66 4 2.66 2.54 2.65 7 2.63 2.56 2.66 14 2.56 2.56 2.70 21 1.46 2.592.70 28 0.25 2.49 2.07 CP₁₄/CP₀ 0.96 >1 >1 CP₂₁/CP₀ 0.55 >1 >1(*inferred based upon 4-day measurement . . . actual value notmeasured).

The magnitude of the initial cure potential for the diluted samples isnoticeably lower than that of CS1 and S1-S3. This reduction in initialcure potential is most likely the result of the increased surface areaof the larger 16-oz. jar leading to a reduced efficiency ofincorporation of peroxide into the flat squares as compared to thepelletized material. Despite this reduction in initial cure potential,an excellent retention of cure potential, as represented by the ratio ofCP₁₄/CP₀, has been maintained for all of the dilution samples.

Example 5

Prepare one comparative sample (“CS2”) and three samples (“S7-S9”)according to the formulations listed in Table 7, below.

TABLE 7 Compositions of CS2 and S7-S9 Component (wt %) S7 S8 S9 CS2 LDPE99.13 99.38 99.5 99.63 DSTDP 0.23 0.23 0.23 0.23 Cyanox ™ 1790 0.14 0.140.14 0.14 Ethylene/aminoacrylate “A” 0.5 0.25 0.13 0 Preblend Total: 100100 100 100 Peroxide Soak: Preblend (wt %) 98.2 98.2 98.2 98.2 DicumylPeroxide (wt %) 1.8 1.8 1.8 1.8 Aminoacrylate Content: Aminoacrylatecontent in 100 50 25 0 composition (ppm) Approximate micromoles of 0.580.29 0.15 0 amine groups per gram of composition

The sample formulations shown in Table 7 are prepared according to thefollowing procedure. The LDPE, DSTDP and Cyanox 1790 are melt compoundedtogether in a Brabender mixing bowl at 130° C. and 30 rpm, by firstmelting the LDPE and then adding the antioxidants, and mixing for 1minute. The aminoacrylate copolymer is added to the melt in theBrabender mixing bowl and mixing is continued for 5 minutes at 130° C.and 30 rpm. The resulting compositions are pressed, cooled, and cut intostrips to feed into a single-screw extruder. Extrusion is performed at200° C. melt temperature to form strands that can be pelletized intoapproximately ⅛″ diameter pellets.

Next, the dicumyl peroxide is soaked into the samples as follows. First,100 g of pellets of the preblend are pre-heated in an oven for 4 hoursat 70° C. in 8-oz. glass jars. Molten dicumyl peroxide (˜55° C.) isadded to the jars. The jars are sealed with a Mylar™ film under thescrew-on lid, and tumbled, returned to the oven for approximately 15minutes, then tumbled or shaken again to ensure that the pellet surfaceis dry (indicating the peroxide has been absorbed). The pellets are thenallowed to soak overnight in the oven at 70° C.

Samples are removed from the jar to evaluate the cure potential as afunction of thermal aging time. The samples are heat aged and their curepotential is determined using a Moving Die Rheometer (MDR) according tothe procedures described above. Results of these analyses are providedin Table 8, below.

TABLE 8 Heat-Aged Cure Potential Retention of CS2 and S7-S9 (valueslisted represent Mh in in-lbs) Days at 70° C. S7 S8 S9 CS2 0 3.12 3.283.23 3.30 4 3.23 3.30 3.21 3.21 7 3.23 3.33 3.20 3.26 14 3.24 3.37 3.241.87 21 3.25 3.44 1.86 0.17 28 3.25 2.47 0.17 0.17 CP₁₄/CP₀ >1 >1 >10.57 CP₂₁/CP₀ >1 >1 0.58 0.05

The revised dilution scheme of samples S7-S9 and CS2, more similar tothe preparation of samples CS1 and S1-S3, yields a more reproducibleinitial torque (as compared to Table 3). Here, a consistent trend hasbeen established in the effectiveness of the amine functionality topreserve the cure potential of the composition. The retention of thecure potential based upon 14 days of heat aging has been maintained withas little as 25 ppm of aminoacrylate or an equivalent of 0.15 micromolesof amine.

The invention claimed is:
 1. A crosslinkable polymeric composition,consisting of: (a) an ethylene-based amine-functionalized interpolymerhaving incorporated therein at least one type of amine-containingmonomer, wherein said ethylene-based amine-functionalized interpolymercomprises an ethylene/aminoacrylate copolymer, wherein saidethylene/aminoacrylate copolymer comprises a copolymer of low-densitypolyethylene grafted with an aminoacrylate monomer selected from thegroup consisting of 2-(diethylamino)ethyl methacrylate,2-(t-butylamino)ethyl methacrylate, and mixtures thereof; (b) an organicperoxide; and (c) optionally, one or more additives; wherein saidethylene-based amine-functionalized interpolymer is present in an amountranging from 80 to 99 weight percent, based on the entire crosslinkablepolymeric composition weight; wherein said organic peroxide is presentin an amount ranging from 0.1 to 5 weight percent, based on the entirecrosslinkable polymeric composition weight; and wherein said one or moreadditives are selected from the group consisting of: antioxidants,crosslinking coagents, processing aids, fillers, coupling agents,ultraviolet absorbers or stabilizers, antistatic agents, nucleatingagents, slip agents, plasticizers, lubricants, viscosity control agents,tackifiers, anti-blocking agents, surfactants, extender oils, acidscavengers, flame retardants, and metal deactivators; wherein thecrosslinkable polymeric composition has an initial cure potential (CP₀)when crosslinked immediately upon preparation of the crosslinkablepolymeric composition and measured as maximum torque (in-lbs) by movingdie rheometer at 182° C., wherein the crosslinkable polymericcomposition has a heat-aged cure potential CP₁₄ when crosslinked afteraging the crosslinkable polymeric composition at 70° C. and ambientpressure for 14 days and measured as maximum torque (in-lbs) by movingdie rheometer at 182° C., and wherein the crosslinkable polymericcomposition has a ratio of CP₁₄ to CP₀ of at least 0.6.
 2. Thecrosslinkable polymeric composition of claim 1, wherein saidaminoacrylate monomer is 2-(diethylamino)ethyl methacrylate.
 3. Thecrosslinkable polymeric composition of claim 1, wherein saidethylene-based amine-functionalized interpolymer is present in an amountsufficient to result in a molar amine content in the range of from 0.1to 200 micromoles of amine per gram of said crosslinkable polymericcomposition.
 4. The crosslinkable polymeric composition of claim 1,wherein said aminoacrylate monomer is 2-(t-butylamino)ethylmethacrylate.